Wrist pin lock



VDec. 27,v 1938. H..- c. MARSH 2,141,720

WRIST PIN LOCK Filed Jan. l2, 1937 /y/e/Q C Mmes/$4 yWmWfrrX v Patented Dec. 27, 1938 UNITED STATESPATENT WRIST PIN LOCK Harry C. Marsh, Long Beach, Calif., assigner of one-fourth to Elton Richardson, Long Beach, Calif.

Application January 12, 1937, Serial No. 120,191

Claims. (Cl. i4- 600) My invention relates to wrist pins and means The outer face of nut I5 is provided with cross for positively locking the same to crank arms, grooves I6 for the reception of a cotter pin Il, and the principal object of my invention is to and which latter passes through an aperture I8 providefrelatively simple, practical and elcient that is formed in the threaded portion of the 5 means whereby a wrist pin may be adjustably Wrist pin. Thus after the nut has been tightened 5 f positioned upon a crank and positively locked on the projecting threaded end. of the wrist pin, or secured against becoming loose while in service. the cotter pin is inserted through one of the In various mechanisms, and particularly in cross grooves i6 and the aligned aperture I8 well drilling and pumping rigs, motion is transthus positively securing the nut on the wrist pin.

1uv mitted to a, walking beam by means-0f a pitman, A Washer I9 is interposed between the nut l5 10 which latter is connected to and operated by a and adjacent face of the Crank H. Formed inwrist pin that is carried by the crank arm of a tesral with the central portion of the Wrist pin rotating shaft. is a square or non-circular block 2t, which pro- It is one of the principal objects of my inven- Vides a shoulder that fits directly against the )tion 130 generally improve upon and Simplify the face Of the Crank H OIJDOSS the face agSLLlSt 15 construction of the wrist pin and to combine which the Washer I@ is positioned and that portherewith simple and efcient means for position 2| of the wrist pin that projects outwardly tively securing the Wrist pin in its adjusted posifrom block receives the end of a pitman 22.

tion upon the crank arm so as to overcome the Arranged on both sides of the head of the pit- 20 possibility of the wrist pin from becoming loose man that iS 111011111386- On the Wrist Din are WaSh- 20 and disengaged from the crank arm. ers 22a, one of which bears against the outer face With the foregoing and other objects in View of block 2li) and these Washersv and the pitman my invention consists in certain novel features are retained o-n the wrist pin in any suitable Y of construction and arrangement of parts that manner, preferably by a Cotter pin 23 that passes 25 will be hereinafter more fully described and through an aperture 24 in the end 0f the Wrist 25 claimed and illustrated in the accompanying Dndrawing, in which: The means utilized for securing the wrist pin Fig. 1 is an elevational view of a crank arm against rotation in the crank arm, comprises a and showing a pitman: connected thereto by plate 25, having a square or rectangular opening means of my improved wrist pin. 26 that receives the block 2B, and projecting 30 Fig. 2 is a horizontal section taken on the line from one side oi plate 25 ODPOS@ the end in 2-2 of Fig. 1. which opening 26 is formed is a stud or pin 21 Fig. 3 is a p1an view of a nut that is utilized that is adapted to t in any one of the aporin securing the wrist pin to the crank arm. tures I2. Fig. 4 is a perspective view of the wrist pin. As a result of the construction just described, 35

Fig. 5 is a perspective View of the member the wrist pin may be lOCated l any 011 0f the utilized between the wrist pin and crank arm for apertures I2 in the crank arm and the plate 25 holding the wrist pin against rotary movement. mounted on the block 21D is positioned against Referring by numerals to the accompanying the outer face of the crank arm with the stud drawing which illustrates a preferred embodior pin 21 seated in theaperture I2, adjacent the 40 ment of my invention, Ill designates ashaft which aperture in which the wrist pin is seated.

is driven in any suitable manner, for instance, The engagement of the non-circular block 2l! by a belt and belting wheel, as illustrated in Fig. in the non-circular opening 26, effectively holds 2, and secured on said shaft is one end of a the wrist pin against rotation and the nut I5 crank arm II. Formed in said crank arm is a and Cotter pin I1 mounted on one end of the 45 series of apertures I2, preferably spaced equiwrist pin eiectively retain the wrist pin in proper distant apart. position on the crank arm.

One end portion of a wrist pin I3 is adapted To achieve the desired results, the block 20 to pass through any one of the apertures. I2, and the opening 26 that receives said block thus enabling said wrist pin to be adjusted` to should be either square in shape, as illustrated 50 various distances away from the axis of shaft I0, in Figs. 4 and 5, or some other symmetrical anguand the end of that portion of the wrist pin that lar shape; for instance an equi-lateral trianguprojects through any one of the apertures I2 lar, a true pentagon orhexagon. is threaded, as designated by I4 for the recep- Such construction enables the wrist pin 2| to tion of a nut I5. be adjusted into a plurality of different positions 55 corresponding to the movement of faces on the edge of block 20 and the corresponding faces in aperture 26, and thus compensate for any irregu- Y Y lar Wear of the pitman on that portion of the Wrist pin with which it is engaged.

This particular advantage materially increases the life or period of service oi the WristV pin.

Thus it will be seen that I have vprovided a Wrist pin lock that is relatively simple'in construction, inexpensive of manufacture,V and very eective in performing the functions for which it is intended. Y

The device comprises fewV parts that are inexpensive of manufacture, and Which parts are capable of being easily and quickly assembled or taken apart.

It will be understood that minor changes in the size, form and construction of the various parts of my improved wrist pin lock may be made and substituted for those herein shown and described Without departing from the spirit of the invention, the scope of which is set forth in the appended claims.

I claim as my invention: p

1. The combination With a crank armV provided with a row of spaced apertures, a Wrist pin having one end adapted to be inserted through any one of the apertures in said crank arm, a symmetrical non-circular b-lock formed integral with the intermediate portion of said Wrist pin, a separately formed plate provided with a symmetrical non-circular opening for the reception of the block on said wrist pin said block and plate being substantially equal in thickness, andV a stud projecting laterally from said plate for engagement in one of the apertures in said crank arm.

2. The combination witha crank arm provided with a roW of spaced apertures, a wrist pin hav-V ing one end adapted to be inserted through any one of the apertures in said crank arm, a symmetrical non-circular block formed integral With the intermediate portion of said Wrist pin, a sep- Y arately formed plate provided with a symmetrical non-circular opening for the reception of the block on said Wrist pin said block and plate being substantially equal in thickness, a stud projectingrlaterally from said plate for engagement in one of the apertures in said crank arm, and

A means mounted on the end of the Wrist pin that projects through said crank arm for securing said wrist pin-to said crank arm.V

3. In a Wrist pin lock, the combination with a cal non-circular block formed on said Wrist pin and bearing against the crank arm in which the Wrist pin is seated, a plate provided with a symmetrical non-circular opening for the reception of the symmetrical non-circular block on said Wrist pin, and a stud projecting laterally from said plate and positioned in the other one of the apertures in said crank arm.

5. The combination With a crank arm provided With a pair of apertures, a Wrist pin having one end seated in one of said apertures, a symmetrical non-circular block formed on said wrist pin and bearing against the crank arm in Which the Wrist pin is seated, a plate provided with a symmetrical non-circular opening for the reception of v the symmetrical non-circular block on said Wrist pin, a stud projecting laterally from, said plate and positioned in the other one of the apertures in said crank arm, and means positioned on the end of the piston that projects through the crank arm for securing said wrist pinto said crank arm.

HARRY C. MARSH. 

